Insular cortex

The insular cortex is a cytoarchitectonically complex and richly connected structure that functions as a cortical hub involved in interoception, multimodal sensory processing, autonomic control, perceptual self-awareness, and emotional guidance of social behavior. The human insula is subdivided into a posterior and an anterior lobe and includes posterior, middle, and anterior subdivisions based on different cytoarchitectonics (granular, dysgranular, and agranular), connectivity, and functions. The posterior (granular) insula receives inputs from pain, temperature, visceral, vestibular, and other sensory pathways; this multimodal sensory representation is further elaborated in the midinsular (dysgranular) cortex and then conveyed to the anterior (agranular) insula, which further processes this information and interacts with areas involved in cognitive and emotional control. The insula thus provides an interface between bodily sensation and emotion and may have a key role in perceptual awareness, social behavior, and decision making. fMRI and cortical microstimulation studies in patients undergoing evaluation for epilepsy surgery have provided further insight into the functional complexity of the insula in humans. Acute lesions, seizures, or degenerative disorders affecting the insula result in a wide range of sensory, autonomic, motor, cognitive, and behavioral manifestations. There are several reviews on the anatomic and functional organization of the insula1–6 and the clinical manifestation of focal lesions, seizures, or degenerative processes involving this complex area7–10